xe2x80x9cNot applicablexe2x80x9d
xe2x80x9cNot applicablexe2x80x9d
xe2x80x9cNot applicablexe2x80x9d
This invention relates to improvements in slotted cable antenna structures. It represents a simpler construction than that claimed in my earlier U.S. Pat. No. 4,464,665, Aug. 7, 1984, Watts, Jr., xe2x80x9cSlotted Cable Antenna Structure,xe2x80x9d but it accomplishes a similar result. An embodiment of this invention is useful as an element in frangible antenna arrays such as may be employed in UHF glide slope ground stations of the Instrument Landing System (ILS).
This slotted cable antenna is built on a length of standard semi-rigid rf transmission line having a number of slots (gaps) cut around the circumference of its outer conductor. Associated with each slot is a shunt conductor, the length of which is adjusted to control the amount of rf energy which escapes through that slot. Between each slot, the semi-rigid line is bend into a meander (loop) to introduce controlled delay in the radiated rf energy from the following slot. The meander is by-passed with a solder connection to maintain continuity of antenna current with the chosen physical slot spacing, typically half-wavelength, approximately.